氯化锂降膜吸收除湿过程研究
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摘要
传统的空调制冷方式以消耗电能为主，随着制冷空调的普及应用，传统的制冷方法导致了目前令人们关注的两大问题：能源问题和环境问题。能源问题是由于传统的压缩式制冷空调消耗大量的电能，引起电能的紧张局势；环境问题是由于传统的氟利昂制冷剂工质造成的臭氧层破坏。液体除湿空调系统是一种环保节能的新型空调方式，液体除湿空调系统可以利用太阳能、工业余热等低品位热源作为再生热源，该系统中没有氟利昂制冷工质，对环境没有污染，能够有效地缓解空调应用引起的能源和环境问题。
本文介绍了液体除湿技术的研究背景和发展现状，从液体除湿技术的基本原理出发，利用实验室现有条件，建立了液体除湿和再生实验台。
进行了以氯化锂水溶液为除湿溶液的绝热填料塔除湿过程实验，考察气液各进口参数对各出口参数值的影响。空气入口温度对除湿影响最小，除湿效果与溶液温度、浓度、流量和空气流量、湿度关系密切。
进行了氯化锂溶液立管降膜再生过程实验研究，在可选择的实验参数范围内，通过实验考察了空气和氯化锂溶液各进口参数变化对再生效果的影响。空气温度、流量和溶液流量对再生脱水量影响很小，随溶液温度、浓度和空气流量变化明显。
分别建立了填料塔除湿和立管降膜再生模型，模拟结果与实验结果趋势一致，通过实验值与模型计算值比较，模型计算值与实验值偏差在20％内。可以利用模型考查各因素对除湿和再生的影响，指导实验和设计。除湿和再生对各参数的依赖性不尽相同。除湿量对溶液的入口浓度、温度、流量，空气的入口湿度具有较强的依赖性，而空气的流量和温度对其影响较小。由于再生降膜管径较小，液气比偏高，空气出口状态与入口状态关系不大，随着空气流量增大，再生器脱水量线性增加，随湿度和温度变化不明显；再生器脱水量与空气流量，溶液温度和浓度关系密切，脱水量随流量缓慢增大。
The traditional compression refrigeration systems consume plenty of electrical energy. With the development and widely application of the technology of refrigeration and air conditioning, the traditional way of refrigeration has resulted in two severe problems concerned by people presently, which are the issues about energy and environment. The expense of plenty of electrical energy leads to the issue about energy. The issue about environment is provoked by the extensive use of traditional refrigerant-Freon. Liquid dehumidification was driven by low temperature heat resource like solar energy. What's more, there is no Freon refrigerant in the new system and no pollution effect.
This article introduced the background and developmental condition of the liquid dehumidification and expatiated on the theory of the dehumidification system. The liquid dehumidification facility was set up.
This thesis observed the change of dehumidification in the different inlet condition. The result of the absorption was accorded with the predictions. Air flow rate, liquid temperature and concentration had a great affect on dehumidification; liquid flow rate, air temperature and humidity had less effect on dehumidification.
The effect of each inlet condition on regeneration in tube falling-film was study in the article. The result of the absorption was accorded with the predictions. The mass of water evaporation was heavy influenced by the liquid temperature and concentration; the air condition had less effect on regeneration.
The mathematic models were established according to the packed tower dehumidification and tube falling-film regeneration, which described heat transfer and mass transfer about the countercurrent flow in the dehumidifier and regenerator of the air conditioning system. The affect of all inlet condition on dehumidification and regeneration was study based the models. The result of the absorption was accorded with the predictions. Air humidity, liquid temperature and concentration had great affect on dehumidification; the mass of water evaporation was heavy influenced by the liquid temperature and concentration; other factor had less effect on dehumidification and regeneration.
本文介绍了液体除湿技术的研究背景和发展现状，从液体除湿技术的基本原理出发，利用实验室现有条件，建立了液体除湿和再生实验台。
进行了以氯化锂水溶液为除湿溶液的绝热填料塔除湿过程实验，考察气液各进口参数对各出口参数值的影响。空气入口温度对除湿影响最小，除湿效果与溶液温度、浓度、流量和空气流量、湿度关系密切。
进行了氯化锂溶液立管降膜再生过程实验研究，在可选择的实验参数范围内，通过实验考察了空气和氯化锂溶液各进口参数变化对再生效果的影响。空气温度、流量和溶液流量对再生脱水量影响很小，随溶液温度、浓度和空气流量变化明显。
分别建立了填料塔除湿和立管降膜再生模型，模拟结果与实验结果趋势一致，通过实验值与模型计算值比较，模型计算值与实验值偏差在20％内。可以利用模型考查各因素对除湿和再生的影响，指导实验和设计。除湿和再生对各参数的依赖性不尽相同。除湿量对溶液的入口浓度、温度、流量，空气的入口湿度具有较强的依赖性，而空气的流量和温度对其影响较小。由于再生降膜管径较小，液气比偏高，空气出口状态与入口状态关系不大，随着空气流量增大，再生器脱水量线性增加，随湿度和温度变化不明显；再生器脱水量与空气流量，溶液温度和浓度关系密切，脱水量随流量缓慢增大。
The traditional compression refrigeration systems consume plenty of electrical energy. With the development and widely application of the technology of refrigeration and air conditioning, the traditional way of refrigeration has resulted in two severe problems concerned by people presently, which are the issues about energy and environment. The expense of plenty of electrical energy leads to the issue about energy. The issue about environment is provoked by the extensive use of traditional refrigerant-Freon. Liquid dehumidification was driven by low temperature heat resource like solar energy. What's more, there is no Freon refrigerant in the new system and no pollution effect.
This article introduced the background and developmental condition of the liquid dehumidification and expatiated on the theory of the dehumidification system. The liquid dehumidification facility was set up.
This thesis observed the change of dehumidification in the different inlet condition. The result of the absorption was accorded with the predictions. Air flow rate, liquid temperature and concentration had a great affect on dehumidification; liquid flow rate, air temperature and humidity had less effect on dehumidification.
The effect of each inlet condition on regeneration in tube falling-film was study in the article. The result of the absorption was accorded with the predictions. The mass of water evaporation was heavy influenced by the liquid temperature and concentration; the air condition had less effect on regeneration.
The mathematic models were established according to the packed tower dehumidification and tube falling-film regeneration, which described heat transfer and mass transfer about the countercurrent flow in the dehumidifier and regenerator of the air conditioning system. The affect of all inlet condition on dehumidification and regeneration was study based the models. The result of the absorption was accorded with the predictions. Air humidity, liquid temperature and concentration had great affect on dehumidification; the mass of water evaporation was heavy influenced by the liquid temperature and concentration; other factor had less effect on dehumidification and regeneration.
引文
[1] 罗清海，汤广发．热管技术在通风空调中的应用[J]．煤气与热力，2005，25(2)：72-75
[2] 丁云飞，丁静，杨晓西．液体干燥剂除湿式燃气空调[J]．煤气与热力，2003，23(12)：738-740
[3] 熊军，刘泽华，寇广孝．燃气驱动液体除湿空调系统[J]．煤气与热力，2004，24(8)：448-450
[4] Kessling W, Laevemann E. Energy storage for desiccant Cooling systems component development [J]. Solar Energy, 1998, 64(4):209-221
[5] Robison H. Liquid Desiccant Solar Heat Pump for Developing Nations[C]. The Symposium Workshop on Solar Energy. Cairo, Egypt, 1978
[6] Kaushik S V. Mass transfer in packed bed reconentration of lithium bromide for open cycle absorption cooling [D]. Fort Collins: Colorado State University, 1984
[7] Lyer R. Packed bed reconentration of lithium chloride solution in an open cycle absorption cooling [D]. Fort Collins: Colorado State University, 1984.
[8] Ertas A, Anderson E E. Properties of a new liquid desiccant solution-Lithium chloride and calcium chloride mixture [J]. Solar Energy, 1992, 49(3): 205-212
[9] 杨英，李心钢．液体除湿特性的试验研究[J]．太阳能学报，2000，21(2)：155-159
[10] Patterson M R, Rerez-Blanco H. Numerical fits of the properties of lithium-bromide water solution [J]. ASHRAE Trans, 1988, 96(2): 2059-2077
[11] Ahmed S Y, Gandhidasan P, Al-Farayedhi A A. Thermodynamic analysis of liquid desiccants [J]. Solar Energy, 1998, 62(1): 11-18
[12] Manuel R. Properties of aqueous solutions of lithium and calcium chlorides: formulations for use in air conditioning equipment design [J]. International Journal of Thermal Sciences, 2004, 43 (4): 367-382
[13] Oberg V, Goswami D Y. Experimental study of the heat and mass transfer in a packed bed liquid desiccant air dehumidifier [J]. Journal of Solar Energy Engineering, 1998, 120(4): 289-297
[14] Arshad Y, Jorge L. Modeling and parametric analysis of heat and mass transfer performance of a hybrid liquid desiccant absorber [J]. Energy Converts, 1998, 39(10): 1095-1112
[15] Rahaman A, Elsayed M M, Al-Najem N M. A numerical solution for cooling and dehumidification of air by a falling desiccant film in parallel flow [J]. Renewable Energy, 1998, 13(3):305-322
[16] Ali A, Vafai K. An investigation of heat and mass transfer between air and desiccant film in an inclined parallel and counter flow channels [J]. International Journal of Heat and Mass Transfer, 2004, 47(8): 1745-1760,
[17] Armanto C O, Clito F A, Saffa B R, Prince S. Thermal performance of a novel air conditioning system using a liquid desiccant[J]. Applied Thermal Engineering, 2000, 20(13): 1213-1223
[18] Haim M F, Grossman G. A packed bed dehumidifier/regenerator for solar air conditioning with liquid desiccants [J]. Solar Energy, 1980,24(6): 541-550
[19] Samam W Y, Alizadeh S. Modeling and performance analysis of a cross-flow Type plate heat Exchanger for dehumidification/cooling [J]. Solar Energy, 2001, 170(4): 361-372
[20] 袁一军．新型绿色空调——Genius~∧R湿能空调器应用前景分析[J]．建筑热能通风空调，2000，19(1)：18-20
[21] 朱瑞琪，李怀富．液体除湿型空调系统中吸收器的工作模拟和实验[J]．流体工程，1992，120(2)：56-59
[22] 赵云．太阳能液体除湿空调系统的研究[D]．南京：东南大学动力工程系，2002
[23] 王明华．Li-H2O液体吸收式除湿系统的研究[D]．北京：北京化工大学化学工程系，2005
[24] Gandhidasan P, Ullah U R. Calculation of heat and mass transfer coefficients in a packed tower operating with a desiccant-air contact system [J]. Journal of Solar Energy Engineering, 1986, 108(5): 123-127
[25] Gandhidasan P, Ullah U, Kettleborough C E Analysis of heat and mass transfer between a desiccant-air system in a packed tower [J]. Journal of Solar Energy Engineering, 1987, 109(5): 89-93
[26] Khan A Y. Parametric analysis of heat and mass transfer performance of a packed-type liquid desiccant absorber at part-load operation conditions [J]. ASHRAE Transactions, 1996, 102(1): 349-357
[27] Haim M, Grossman G. A packed bed dehumidifier regenerator for solar air conditioning with liquid desiccants. Solar Energy, 1980, 24(6): 541-550
[28] Gandhidasan P U, KeUleborough M R. Analysis of heat and mass transfer between a desiccant air system in a packed tower. Transactions of the ASME Journal of Solar Energy Engineering, 1987, 109(2): 89-93
[29] Khan A Y. Sensitivity analysis and component modeling of a packed-type liquid desiccant system at partial load operating conditions. International Journal of Energy Research, 1994, 18(7): 643-655
[30] Khan A Y, Ball H D. Development of a generalized model for performance evaluation of packed-type liquid sorbet dehumidifiers and regenerators [J]. ASHRAE Trans, 1992, 98(1): 525-533
[31] Stevens D I, Braun J E. An effectiveness model of liquid-desiccant system heat/mass exchangers [J]. Solar Energy, 1989, 42(6): 449-455
[32] Sadasiva M, Balakrishnan A R. Effectiveness-NTU method for design of a packed bed liquid desiccant dehumidifiers [J]. Transactions of the Institution of Chemical Engineers, 1992, 70(2): 572-577
[33] Grossman G. Simultaneous heat and mass transfer in film absorption under laminar flow [J]. International Journal of Heat and Mass Transfer, 1983, 26(3): 357-371
[34] Grossman G. Simultaneous heat and mass transfer in absorption of gases in turbulent liquid films [J]. International Journal of Heat and Mass Transfer, 1984, 27(12): 2365-2376
[35] Yang R, Wood B D. A numerical modeling of an absorption process on a liquid falling film [J]. Solar Energy, 1992, 48(3): 195-198
[36] 代彦军，张鹤飞．错流降膜液体干燥剂除湿／再生传热传质数学模型及分析[J]．化工学报，2001，52(6)：510-515
[37] 方承超，孙克涛．太阳能液体除湿空调系统模型的建立与分析[J]．太阳能学报，1997，18(2)：128-133
[38] 路则锋，陈沛霖．逆流填料式液体除湿系统传热传质过程的分析解法及应用[J]．太刚能学报，2000，21(4)：339-446
[39] 路则锋．填料式液体除湿系统传递过程理论解及验证[J]．同济大学学报，2001，29(2)：149-153
[40] 路则锋．填料式液体除湿系统设计计算的ε-NTU法[J]．暖通空调，2002，32(3)：126-128
[41] 赵云，施明恒．太阳能液体除湿空调中除湿剂的选择[J]．工程热物理学报，2001，22(增刊)：165-168
[42] 张立志，除湿技术．北京：化学工业出版社，2005
[43] 何潮洪，冯霄．化工原理[M]．北京：科学出版社，2001
[44] 陈钟秀，顾飞燕．化工热力学[M]．北京：化学工业出版社，1998
[45] 方承超，黄强华．太阳能液体除湿空凋系统研究现状．新能源，1995，17(7)：8-11
[46] 王树楹．现代填料塔技术指南．北京：中国石化出版社，1998
[47] 铃木谦一郎，大矢信男．除湿没计[M]．北京：中国工业出版社，1983
[48] 刘乃鸿．工业塔新型规整填料应用手册．天津：天津天津大学出版社，1993
[49] 王运东，骆广生，刘谦．传递过程原理[M]．北京：清华大学出版社，2002
[2] 丁云飞，丁静，杨晓西．液体干燥剂除湿式燃气空调[J]．煤气与热力，2003，23(12)：738-740
[3] 熊军，刘泽华，寇广孝．燃气驱动液体除湿空调系统[J]．煤气与热力，2004，24(8)：448-450
[4] Kessling W, Laevemann E. Energy storage for desiccant Cooling systems component development [J]. Solar Energy, 1998, 64(4):209-221
[5] Robison H. Liquid Desiccant Solar Heat Pump for Developing Nations[C]. The Symposium Workshop on Solar Energy. Cairo, Egypt, 1978
[6] Kaushik S V. Mass transfer in packed bed reconentration of lithium bromide for open cycle absorption cooling [D]. Fort Collins: Colorado State University, 1984
[7] Lyer R. Packed bed reconentration of lithium chloride solution in an open cycle absorption cooling [D]. Fort Collins: Colorado State University, 1984.
[8] Ertas A, Anderson E E. Properties of a new liquid desiccant solution-Lithium chloride and calcium chloride mixture [J]. Solar Energy, 1992, 49(3): 205-212
[9] 杨英，李心钢．液体除湿特性的试验研究[J]．太阳能学报，2000，21(2)：155-159
[10] Patterson M R, Rerez-Blanco H. Numerical fits of the properties of lithium-bromide water solution [J]. ASHRAE Trans, 1988, 96(2): 2059-2077
[11] Ahmed S Y, Gandhidasan P, Al-Farayedhi A A. Thermodynamic analysis of liquid desiccants [J]. Solar Energy, 1998, 62(1): 11-18
[12] Manuel R. Properties of aqueous solutions of lithium and calcium chlorides: formulations for use in air conditioning equipment design [J]. International Journal of Thermal Sciences, 2004, 43 (4): 367-382
[13] Oberg V, Goswami D Y. Experimental study of the heat and mass transfer in a packed bed liquid desiccant air dehumidifier [J]. Journal of Solar Energy Engineering, 1998, 120(4): 289-297
[14] Arshad Y, Jorge L. Modeling and parametric analysis of heat and mass transfer performance of a hybrid liquid desiccant absorber [J]. Energy Converts, 1998, 39(10): 1095-1112
[15] Rahaman A, Elsayed M M, Al-Najem N M. A numerical solution for cooling and dehumidification of air by a falling desiccant film in parallel flow [J]. Renewable Energy, 1998, 13(3):305-322
[16] Ali A, Vafai K. An investigation of heat and mass transfer between air and desiccant film in an inclined parallel and counter flow channels [J]. International Journal of Heat and Mass Transfer, 2004, 47(8): 1745-1760,
[17] Armanto C O, Clito F A, Saffa B R, Prince S. Thermal performance of a novel air conditioning system using a liquid desiccant[J]. Applied Thermal Engineering, 2000, 20(13): 1213-1223
[18] Haim M F, Grossman G. A packed bed dehumidifier/regenerator for solar air conditioning with liquid desiccants [J]. Solar Energy, 1980,24(6): 541-550
[19] Samam W Y, Alizadeh S. Modeling and performance analysis of a cross-flow Type plate heat Exchanger for dehumidification/cooling [J]. Solar Energy, 2001, 170(4): 361-372
[20] 袁一军．新型绿色空调——Genius~∧R湿能空调器应用前景分析[J]．建筑热能通风空调，2000，19(1)：18-20
[21] 朱瑞琪，李怀富．液体除湿型空调系统中吸收器的工作模拟和实验[J]．流体工程，1992，120(2)：56-59
[22] 赵云．太阳能液体除湿空调系统的研究[D]．南京：东南大学动力工程系，2002
[23] 王明华．Li-H2O液体吸收式除湿系统的研究[D]．北京：北京化工大学化学工程系，2005
[24] Gandhidasan P, Ullah U R. Calculation of heat and mass transfer coefficients in a packed tower operating with a desiccant-air contact system [J]. Journal of Solar Energy Engineering, 1986, 108(5): 123-127
[25] Gandhidasan P, Ullah U, Kettleborough C E Analysis of heat and mass transfer between a desiccant-air system in a packed tower [J]. Journal of Solar Energy Engineering, 1987, 109(5): 89-93
[26] Khan A Y. Parametric analysis of heat and mass transfer performance of a packed-type liquid desiccant absorber at part-load operation conditions [J]. ASHRAE Transactions, 1996, 102(1): 349-357
[27] Haim M, Grossman G. A packed bed dehumidifier regenerator for solar air conditioning with liquid desiccants. Solar Energy, 1980, 24(6): 541-550
[28] Gandhidasan P U, KeUleborough M R. Analysis of heat and mass transfer between a desiccant air system in a packed tower. Transactions of the ASME Journal of Solar Energy Engineering, 1987, 109(2): 89-93
[29] Khan A Y. Sensitivity analysis and component modeling of a packed-type liquid desiccant system at partial load operating conditions. International Journal of Energy Research, 1994, 18(7): 643-655
[30] Khan A Y, Ball H D. Development of a generalized model for performance evaluation of packed-type liquid sorbet dehumidifiers and regenerators [J]. ASHRAE Trans, 1992, 98(1): 525-533
[31] Stevens D I, Braun J E. An effectiveness model of liquid-desiccant system heat/mass exchangers [J]. Solar Energy, 1989, 42(6): 449-455
[32] Sadasiva M, Balakrishnan A R. Effectiveness-NTU method for design of a packed bed liquid desiccant dehumidifiers [J]. Transactions of the Institution of Chemical Engineers, 1992, 70(2): 572-577
[33] Grossman G. Simultaneous heat and mass transfer in film absorption under laminar flow [J]. International Journal of Heat and Mass Transfer, 1983, 26(3): 357-371
[34] Grossman G. Simultaneous heat and mass transfer in absorption of gases in turbulent liquid films [J]. International Journal of Heat and Mass Transfer, 1984, 27(12): 2365-2376
[35] Yang R, Wood B D. A numerical modeling of an absorption process on a liquid falling film [J]. Solar Energy, 1992, 48(3): 195-198
[36] 代彦军，张鹤飞．错流降膜液体干燥剂除湿／再生传热传质数学模型及分析[J]．化工学报，2001，52(6)：510-515
[37] 方承超，孙克涛．太阳能液体除湿空调系统模型的建立与分析[J]．太阳能学报，1997，18(2)：128-133
[38] 路则锋，陈沛霖．逆流填料式液体除湿系统传热传质过程的分析解法及应用[J]．太刚能学报，2000，21(4)：339-446
[39] 路则锋．填料式液体除湿系统传递过程理论解及验证[J]．同济大学学报，2001，29(2)：149-153
[40] 路则锋．填料式液体除湿系统设计计算的ε-NTU法[J]．暖通空调，2002，32(3)：126-128
[41] 赵云，施明恒．太阳能液体除湿空调中除湿剂的选择[J]．工程热物理学报，2001，22(增刊)：165-168
[42] 张立志，除湿技术．北京：化学工业出版社，2005
[43] 何潮洪，冯霄．化工原理[M]．北京：科学出版社，2001
[44] 陈钟秀，顾飞燕．化工热力学[M]．北京：化学工业出版社，1998
[45] 方承超，黄强华．太阳能液体除湿空凋系统研究现状．新能源，1995，17(7)：8-11
[46] 王树楹．现代填料塔技术指南．北京：中国石化出版社，1998
[47] 铃木谦一郎，大矢信男．除湿没计[M]．北京：中国工业出版社，1983
[48] 刘乃鸿．工业塔新型规整填料应用手册．天津：天津天津大学出版社，1993
[49] 王运东，骆广生，刘谦．传递过程原理[M]．北京：清华大学出版社，2002